The primary objectives of this study are to determine the clinical and laboratory efficacy of vaccinating HIV-1 infected individuals with CD4 counts >600 cells/mm^3 with the recombinant vaccine MN rgp120/HIV-1. Primary endpoints are stabilization or reduction in the rate of decline of CD4 cell counts over time in the immunized group when compared to placebo, decline in the incidence of clinical HIV-related events, and a decrease in viral burden in the immunized group when compared to placebo.